Pollination Efficiency of Xylocopa olivacea (Hymenoptera: Apidae) on Phaseolus vulgaris Large White Seed Variety (Fabaceae) Flowers in Ngaoundere (Cameroon)

To evaluate the impact of a single flower visit of Xylocopa olivacea on the production of Phaseolus vulgaris Large White Seed variety, its foraging and pollinating activities were studied at Dang in June 2017 and 2018. The experiments were carried out on 540 flowers labeled at bud stage and divided in four treatments: two differentiated according to the presence or absence of flowers protection regarding insect visits; the third protected and uncovered when flowers were opened, to allow X. olivacea visits and the fourth with the flowers protected, uncovered when they were opened, then rebagged without any visit. Results indicate that among seven insect species recorded on flowers, X. olivacea ranked first and harvested nectar. Throughout the pollination efficiency of a single flower visit, X. olivacea provoked a significant increase of the podding rate and the percentage of normal seeds by 30.45 % and 32.81 % respectively. The conservation and installation of X. olivacea nests close to P. vulgaris var. Large White Seed fields is recommended to improve its pod and seed productions.